A bicycle chain is a complex structure that incorporates different mechanisms with specific and often contradictory lubrication requirements.
In the first place, a bicycle chain operates in a very dusty environment. Accordingly, its lubricant should be non-tacky, that is dry or of a low viscosity so as not to collect dust, and thereby encourage abrasion. This requirement would normally exclude greases in favor of solid lubricants. However, the unbalanced and relatively high pressure applied by the rollers of the chain against their cross axis call for a grease-type lubricant. Moreover, the shearing contact between the teeth of the driving sprockets and the outside surface of the beads can benefit from the bearing pressure provided by a grease as well as an adsorbed layer of a thin-film lubricant.
These problems have been addressed by a lubricant which in one embodiment comprises an insoluble soap dispersed in a volatile solvent-based solution of wax and petrolatum (petroleum jelly) available under the brand name WHITE LIGHTNING, available from Leisure Innovations, Inc., Morro Bay, Calif. This lubricant is described in detail in U.S. Pat. No. 5,472,625, which is incorporated herein by reference. In brief, the lubricant is applied in liquid form in which it penetrates to coat all surfaces of the chain. The solvent then evaporates leaving a solid protective film of wax and petrolatum as modified by the soap to discourage the accumulation of dirt.
This lubricant however, will not properly lubricate when it is applied to a wet chain. Chains can become wet in a variety of ways, such as: rain, cleaning with water or water-based cleaning agents, even cleaning with non-dry compressed air. The lubricant typically cannot penetrate ambient water held by capillary action on the various surfaces of the chain. As the solvent evaporates, the lubricant solidifies leaving portions of the chain un-contacted by lubricant. Some or all of the water may then evaporate, leaving voids between the chain and lubricant. Being solid, the lubricant cannot then flow into the voids. Although instructing the product user that the chain must be dry before applying the lubricant eliminates most of the problem, it is inconvenient for the user.
Accordingly, there is a need for a multi-functional lubricant specifically formulated to allow application on wet or dry bicycle chains and similar mechanisms operating in dusty or wet environments such as powered or manually driven household, gardening, farming, construction and industrial equipment.